1. In the data set, the sum of all the data points, divided by the number of data points; the average. 2. To find the mean, you add up all the data, and then divide by the number of data.
Answer:
because the rivers were a source of food and water and there were many recourses by rivers eg trees
Explanation:
You should search up the answer online it usually pops up the answer.
Wheres the choiceis i cant do it without thim